In an effort to make automobiles more fuel-efficient, automobile exterior designs are becoming more streamlined. To achieve this goal, automobile manufacturers are requiring flush-mounted panel and window assemblies. The goal is to locate the panel or window within the vehicle such that the peripheral edge of the panel or window assembly is recessed and the outer surface of the panel is generally flush with any adjoining body panels. In the case of fixed panels, a conventional technique includes placing or running a bead of adhesive material around the entire inside peripheral edge of the panel and bonding it in the vehicle opening. While satisfactory for stationary windows, this method creates problems with movable windows, however, particularly those which articulate about a hinge.
Conventional articulated or hinged windows are fixed to the vehicle by a mounting assembly which is fastened by a stud passing through a hole drilled in the panel. A low profile nut is then threaded onto the stud extending through the panel to retain the panel thereon. A major disadvantage is that a significant number of glass panels are broken as a result of drilling the holes through the panel. The panels are also broken during or after mounting of the mounting hardware. To avoid the breakage of the glass panel, sophisticated techniques have been adopted to drill the holes, and the mounting hardware has been adapted to reduce breakage. As a result, the price of such panel assemblies is unnecessarily high. Moreover, the resulting panel is not truly flush since the mounting hardware has a positive relief with respect to the panel exterior surface.
Another attempt to reduce the exterior profile of articulated window assemblies is disclosed in U.S. Pat. No. 4,396,221 which employs a channel extending around the edge of the window pane, a flexible resilient portion allowing pivotal movement of the window pane, and one of several types of fasteners. Such fasteners include a clip with a detent received in the seal and securing the hinge and thus the assembly to a pinch weld flange.
Another embodiment of the hinged window assembly just described includes a substantially rectilinear hinge member which includes a retaining end bonded to the exterior or front surface of the window panel by an adhesive and an opposing retaining end having an aperture which receives a metal screw extending into the vehicle body. Seated on the pinch-weld flange is a sealing weather strip which forms a closed bulbous portion engaging both the inside surface of the pane as well as a shoulder of the recess leading to the pinch weld flange on the exterior sheet metal body portion. To conceal the fastener for the hinge, a metal covering extending from the vehicle roof or another portion of the vehicle may extend over the fastener and a substantial portion of the hinge.
A disadvantage associated with each of the above hinged windows is that the hinge member is fixed to the exterior surface of the panel. In addition, in the last embodiment described above, the fastener securing the assembly to the vehicle is exposed, or must include a special cover member. Accordingly, the exterior profile of these window assemblies do not result in a truly flush-mounted, articulated window assembly.
Although known in the art to adhesively bond metal to glass for a variety of purposes such as stud attachments, small hinge plates, etc., known hinge adhesives and hinge designs are inadequate to meet load requirements and long-term environmental resilience required for flush-mounted, hinged window assemblies. Hinge mounting of large size, flush-mounted panels in the nature of van windows is a demanding application of adhesive technology. The higher weight of such a window transmits more severe vibration requiring greater strength and greater long-term environmental resilience and durability than is available with such prior known bonds. Styling and design limitations restrict the number of hinges and the size of the bond areas.
Accordingly, there is now a need for large panels such as van or tailgate windows having a flush mounted hinge, and an improved bond between a hinge member and the single panel surface to which it is attached to support the panel.